Biology subjects

Thornton, A.

Publications and source records attributed to Thornton, A..

11 recordsLinked to original sources

bioRxiv2025

Social relationships promote access to food and information in wild jackdaws

Many social animals form differentiated social relationships that can influence fitness, yet the mechanisms behind these benefits are often unclear. Does the presence of social partners during foraging enhance access to food or information? Might individuals also incur short-term costs, for example by foregoing feeding opportunities to remain with and support social partners? Here, we investigated how social relationships shape foraging decisions and outcomes in wild jackdaws (Corvus monedula) using automated RFID feeding stations where two birds could perch, but only one could feed with the other queueing behind ("dyadic events"). Bonded social partners (pair-bonded mates and direct kin) engaged in these dyadic events more frequently and coordinated their visits, as shown by shorter dyadic arrival latencies. Bonded partners also showed higher social tolerance, with feeding individuals benefitting from increased food intake when their partner was present, while queuing individuals accepted short-term opportunity costs to remain with them. For juveniles, queuing with parents promoted social learning about feeder use. These findings show that social relationships influence decision-making and foraging performance in the wild, revealing both benefits and costs of maintaining close bonds. Short-term effects on foraging success may therefore contribute to long-term fitness advantages of strong social relationships.

animal behavior and cognition↗

bioRxiv2024

Wild jackdaws learn social tolerance to exploit new information

Social tolerance can enhance access to resources and is thought to be crucial in facilitating the evolution of cooperation, social cognition and culture, but it is unknown whether animals can optimise their social tolerance through learning. We presented wild jackdaws (Corvus monedula) with a novel social information problem using automated feeders: to access food, adults had to inhibit their tendency to displace juveniles and instead show tolerance by occupying an adjacent perch. Adults learned to tolerate juveniles, generalising across juveniles as a cohort, demonstrating learning of a new information-use strategy. The ability to learn to tolerate those that provide valuable information, and generalise across cohorts of informed individuals, may facilitate adaptive responses in the face of environmental change and help to explain the success of jackdaws in human-dominated environments.

animal behavior and cognition↗

bioRxiv2024

Anthropogenic noise affects vocalisation properties of the territorial song of Western Australian magpies

Anthropogenic noise is considered one of the most serious forms of pollution globally and has been shown to have negative effects on the distribution, behaviour, cognition and reproductive success of animal species worldwide. One of the most well researched impacts of anthropogenic noise is its effect on acoustic communication. Animals may adjust the rate, amplitude, duration, and/or frequency of their acoustic signals to better maintain communication when anthropogenic noise is present. In this study, we combine behavioural focals, amplitude measurements and audio recordings to investigate how female Western Australian magpies (Gymnorhina tibicen dorsalis) alter the acoustic features of their territorial song (known as a carol) when anthropogenic noise is present. Magpies reduced the rate at which they carolled when loud anthropogenic noise was present, and increased their peak frequency during anthropogenic noise, but, contrary to our hypotheses did not alter the amplitude, duration, or other frequency parameters of their carols. Results from this study add to the growing body of literature documenting changes to the vocal behaviour of wildlife in the presence of anthropogenic noise and highlights the importance of investigating multiple acoustic parameters to understand how species adjust their vocalisations in response to this pollutant.

animal behavior and cognition↗

bioRxiv2023

Pair-bond strength is consistent and related to partner responsiveness in a wild corvid

The need to maintain strong social bonds is widely held to be a key driver of cognitive evolution. This assumes that the maintenance of strong bonds is a stable trait that is cognitively demanding but generates fitness benefits, and so can come under selection. However, these fundamental micro-evolutionary tenets have yet to be tested together within a single study system. Combining observational and experimental behavioural data with long-term breeding records, we tested four key assumptions in wild jackdaws (Corvus monedula), corvids whose long-term pair-bonds exemplify the putative social drivers of cognitive evolution in birds. We found support for three assumptions: (1) pair-bond strength varies across the population, (2) is consistent within pairs over time and (3) is positively associated with a measure of socio-cognitive performance. However, we did not find evidence that stronger pair-bonds lead to better fitness outcomes (prediction 4). While strongly bonded pairs were better able to adjust hatching synchrony to environmental conditions, they did not fledge more or higher quality offspring. Together, these findings provide important evidence that the maintenance of strong pair bonds is linked to socio-cognitive performance and facilitates effective coordination between partners. However, they also imply that these benefits may not be sufficient to explain how selection acts on social cognition. We argue that evaluating how animals navigate trade-offs between investing in long-term relationships versus optimising interactions in their wider social networks will be a crucial avenue for future research.

animal behavior and cognition↗

bioRxiv2022

General cognitive performance declines with female age and is negatively related to fledging success in a wild bird

Identifying the causes and fitness consequences of intraspecific variation in cognitive performance is fundamental to understand how cognition evolves. Selection may act on different cognitive traits separately or jointly as part of the general cognitive performance of the individual. To date, few studies have examined simultaneously whether individual cognitive performance covaries across different cognitive tasks, the relative importance of individual and social attributes in determining cognitive variation, and its fitness consequences in the wild. Here, we tested 38 wild southern pied babblers (Turdoides bicolor) on a cognitive test battery targeting associative learning, reversal learning and inhibitory control. We found that a single factor explained 59.5% of the variation in individual cognitive performance across tasks, suggestive of a general cognitive factor. General cognitive performance varied by age and sex; declining with age in females but not males. Older females also tended to produce a higher average number of fledglings per year compared to younger females. Analysing over 10 years of breeding data, we found that individuals with lower general cognitive performance produced more fledglings per year. Collectively, our findings support the existence of a trade-off between cognitive performance and reproductive success in a wild bird.

animal behavior and cognition↗

bioRxiv2021

Problems with comparative analyses of avian brain size

There are multiple hypotheses for the evolution of cognition. The most prominent hypotheses are the Social Intelligence Hypothesis (SIH) and the Ecological Intelligence Hypothesis (EIH), which are often pitted against one another. These hypotheses tend to be tested using broad-scale comparative studies of brain size, where brain size is used as a proxy of cognitive ability, and various social and/or ecological variables are included as predictors. Here, we test how methodologically robust such analyses are. First, we investigate variation in brain and body size measurements across >1000 species of bird. We demonstrate that there is substantial variation in brain and body size estimates across datasets, indicating that conclusions drawn from comparative brain size models are likely to differ depending on the source of the data. Following this, we subset our data to the Corvides infraorder and interrogate how modelling decisions impact results. We show that model results change substantially depending on variable inclusion, source and classification. Indeed, we could have drawn multiple contradictory conclusions about the principal drivers of brain size evolution. These results reflect recent concerns that current methods in comparative brain size studies are not robust. We add our voices to a growing community of researchers suggesting that we move on from using such methods to investigate cognitive evolution. We suggest that a more fruitful way forward is to instead use direct measures of cognitive performance to interrogate why variation in cognition arises within species and between closely related taxa.

animal behavior and cognition↗

bioRxiv2021

A multivariate view of cognitive differences reveals domain-general correlation structure in the Trinidadian Guppy (Poecilia reticulata)

Cognitive variation is common among-individuals and can be consistent across time and context. From an evolutionary perspective, among-individual variation is important as a pre-requisite for natural selection and adaptive evolution. Selection is widely hypothesized to favor high cognitive performance but directional selection should erode variation over time, how then is cognitive variation maintained? As selection does not act on traits in isolation, covariance among specific cognitive traits and/or other aspects of phenotype (e.g. personality) could result in fitness trade-offs that are important in shaping evolutionary dynamics. Here we test this using Trinidadian guppies (Poecilia reticulata), using a multivariate approach by characterising the correlation structure among task-specific cognitive performance measures and a personality trait. We estimate the among-individual correlation matrix (ID) in performance across three cognitive tasks; colour association learning task; motor learning task; reversal learning task, and the personality trait boldness measured as emergence time from a shelter. We found no support for trade-offs among performance in these tasks. Nor do we find evidence of hypothesised speed-accuracy trade-offs within the association learning task. Rather we find strong positive correlation structure in ID, with 57% of variation explained by the leading eigen vector. While noting that non-cognitive factors and assay composition may affect the structure of ID, we suggest our findings are consistent with the g-model of cognitive performance variation, in which a dominant axis of variation loads positively on all performance measures. Thus, we add to a growing body of support for general variation among individuals in animal cognitive ability.

animal behavior and cognition↗

bioRxiv2020

Cooperative nest building in wild jackdaws

Animals create diverse structures, both individually and cooperatively, using materials from their environment. One striking example are the nests birds build for reproduction, which protect the offspring from external stressors such as predators and temperature, promoting reproductive success. To construct a nest successfully, birds need to make various decisions, for example regarding the nest material and their time budgets. To date, research has focused mainly on species where one sex is primarily responsible for building the nest. In contrast, the cooperative strategies of monogamous species in which both sexes contribute to nest building are poorly understood. Here we investigated the role of both sexes in nest building and fitness correlates of behaviour in wild, monogamous jackdaw pairs (Corvus monedula). We show that both partners contributed to nest building and behaved similarly, with females and males present in the nest box for a comparable duration and transporting material to the nest equally often. However, while females spent more time constructing the nest, males tended to invest more time in vigilance, potentially as a means of coping with competition for nest cavities. These findings suggest a moderate degree of division of labour, which may facilitate cooperation. Moreover, some aspects of behaviour were related to proxies of reproductive success (lay date and egg volume). Females that contributed relatively more to bringing material laid earlier clutches and pairs that spent less time together in the nest box had larger eggs. Thus, selection pressures may act on how nest building pairs spend their time and cooperatively divide the labour. We conclude that cooperative nest building in birds could be associated with monogamy and obligate biparental care, and provides a vital but relatively untapped context through which to study the evolution of cooperation. HighlightsO_LIIn wild monogamous jackdaws, mates behaved similarly and cooperated to build their nest. C_LIO_LIFemales built more and called more frequently; males tended to be more vigilant. C_LIO_LIFemales that contributed relatively more to transporting nest material laid earlier clutches. C_LIO_LIPairs that spent more time together in the nest box had smaller eggs. C_LIO_LICooperation may be crucial in light of obligate biparental care and nest site competition. C_LI

animal behavior and cognition↗

bioRxiv2020

Mobbing-like response to secondary predator cues is not a form of teaching in meerkats

Across many taxa, individuals learn how to detect, recognise and respond to predators via social learning. Learning to recognise and interpret predator cues is essential in the accurate assessment of risk. Cues can come directly from a predators presence (visual, acoustic) or from secondary predator cues (SPCs, such as hair/feathers, urine or faeces) left in the environment. Animals show various responses to encountering SPCs, which are thought to act in reducing risk to the individual. Meerkats, Suricata suricatta, show a response to SPCs not described in any other species: they display a mobbing-like behaviour. The function of this behaviour is unclear as unlike mobbing, the response it so closely resembles, it cannot serve to drive predators away. We used experiments to investigate whether adults may use this mobbing-like response to teach naive young how to recognise and respond to predators. Meerkats are known to teach pups hunting skills, but there is as yet no evidence that any species other than humans teaches across multiple contexts. We used experimental presentations of SPCs to test whether wild adult meerkats respond more intensely to SPCs in the presence of naive pups, as would be expected if the behaviour serves to promote learning. Contrary to this prediction, response intensity was lower when pups were present than when they were absent, and declined as the number of pups in the group increased, possibly due to costs associated with foraging with dependent young. Response intensity instead increased with increasing group size, number of group members interacting with the cue, and varied with predator cue type. These results suggest that the mobbing-like response to SPCs is not a form of teaching in meerkats. Instead, this behaviour may function to increase the recruitment of others to investigate the SPC. Exposing group members to SPCs may better inform them of the nature of the threat, facilitating more effective defensive group responses.

animal behavior and cognition↗

bioRxiv2020

Mobbing-like response to secondary predator cues informs group behaviour in wild meerkats

The assessment of current risk is essential in informing defensive behaviours. Many animals use cues left behind by predators, known as secondary predator cues (SPCs), to assess risk and respond appropriately. However, meerkats, Suricata suricatta, exhibit seemingly unique mobbing-like responses to these cues. The benefit of this high-intensity recruitment response is unclear, as unlike genuine mobbing, it cannot help to drive the predator away. One potential explanation is that mobbing-like responses promote information gathering and collective decision-making by the whole group. To examine this, we investigated (i) how meerkats responses to SPCs differ from mobbing live animals and (ii) the subsequent behavioural changes following a SPC encounter. Using a dataset gathered over a 20-year period, we first compared the rate of SPC recruitment versus the rate of animal mobbing. We then investigated changes in behaviour (alarm calling, sentinel bouts, distance travelled and pup provisioning) in the hour before and after a SPC encounter. Abiotic factors did not affect recruitment rate to SPCs or live animals, or influence the change in behavioural responses following a SPC encounter. The presence of pups reduced response rate to SPCs, but had no effect on animal mobbing rate, supporting experimental findings that responses towards SPCs are unlikely to function as a form of teaching. Alarm calling rate increased and the distance travelled by the group decreased following a SPC encounter, and were unaffected by the presence of pups or abiotic conditions. The results indicate group-level behavioural changes following a SPC encounter, and a greater degree of plasticity in recruitment to SPCs than to live animals. This response plasticity may reflect a context-dependent need to gather information to make collective decisions for defensive behaviour according to the level of threat perceived.

animal behavior and cognition↗

bioRxiv2020

Cognitive performance and stress responsiveness in the Trinidadian Guppy: a multivariate approach

Cognition is vital for carrying out behaviours required for survival and reproduction. In animals, we now know that cognitive performance varies not just among species, but also among individuals within populations. While this variation is a prerequisite for contemporary natural selection, it is also true that selection does not act on traits in isolation. The extent to which cognitive traits covary with other aspects of phenotype (e.g. personality traits) is therefore expected to be an important factor in shaping evolutionary dynamics. Here we adopt a multivariate approach to test for spatial learning ability in a captive population of male Trinidadian guppies (Poecilia reticulata), and ask whether differences in cognitive performance are associated with (repeatable) differences in stress response behaviour. We focus on stress response for two reasons. First, functional links between cognitive traits and stress coping style have been hypothesised. Second, individual-level studies of cognitive performance typically rely on multiple testing paradigms that may themselves be a stressor. Thus, there is a risk that variation in stress responsiveness is itself a cause of apparent, but artefactual variance in cognitive ability. Using a set of fish exposed repeatedly to two distinct spatial learning tasks (maze layouts), and an acute stress response test (open field trial), we find differences among-individuals in task performance that are repeatable within- and across maze layouts. On average performance improves with experience in the first maze, consistent with spatial learning, but not in the second. In both mazes, there is among-individual variation in the trajectory of mean performance with trial number suggesting individuals differ in learning rate. Acute stress response behaviour is repeatable but predicts neither average time to solve the maze nor learning rate. We thus find no support for among-individual correlation between acute stress response and cognitive performance. However, we highlight the possibility that cumulative, chronic stress effects may nonetheless cause observed declines in performance across repeats for some individuals (leading to lack of improvement in mean time to solve the second maze). If so, this may represent a pervasive but difficult challenge for our ability to robustly estimate learning rates in studies of animal cognition.

animal behavior and cognition↗